The fossil laid unnoticed until 2006, when it was chanced upon by visiting dinosaur researcher Mike Taylor from the University of Portsmouth in England.

The museum specimen "leapt out at me as being different," said Taylor, a postdoctoral student whose dinosaur studies focus on giant, long-necked herbivores known as sauropods.

Having spent the previous five years "doing nothing but looking at sauropod vertebrae," he immediately realized the half-complete fossil bone was "something strange," Taylor said.

"It was unmistakably a dorsal vertebra from a sauropod, but it didn't look like any dorsal vertebrae I'd ever seen before."

Investigation of the foot-tall (30-centimeter-tall) fossil subsequently revealed an unknown species that lived some 140 million years ago, according to findings published in the current issue of Palaeontology, the journal of Britain's Palaeontological Association.

The newly named Xenoposeidon proneneukus was likely typical for a sauropod, with a huge body, long neck, and stout legs. But its many unusual spinal features puts it in a new family of dinosaurs, the study says.

"Shockingly Strange"

The study was co-authored by University of Portsmouth paleontologist Darren Naish, who Taylor turned to for assistance in identifying his museum find.

"The fossil is not just a little bit different from the vertebrae of other types of sauropod—it's shockingly strange," Naish said.

"Based on this one bone, Xenoposeidon has more unique features than do other sauropods that are known from almost complete skeletons," he added. "That's how strange it is."